Cutting tool



Nov. 3, 1931.

CUTTING TOOL Filed April 21, 1928 INVENTOR.

PM BY ##L/ A TTORNEYS.

B. F. STOWELL 1,830,179

Pa t enti edNov. 3, 1931', i

UNITED TATes BYRONF STOW-ELL F D N. A S fiSErrsAssrGuoR iro vAiv noRM NMAY CHI-NE'VTOOL' COMPANY,- OF: srRINGF ELi "MASSACHUSETTS Ap neatieafiled April 21,

This invention relates to'cutting tools and will be described withparticular reference to'tools'intended for resurfacing-the carboncoatedand pitted valve seats of internal com-'- bustion engines. It has forits objects the improvement oftools of this type in respect to theircutting ability, their cheapness, and

their Wearing qualities. The 'manner in I Fig.3is a partial perspectiveview'showing the manner in WhlClIthe' blades are secured;

in the. body portion of the cutterg is Fig. 4 is asirnilar' view showinga modified:

"manner'of securing the blades;

Figs. and6 are detailsrespectively of the blades v ock a'ndofa bladeus'ed'in'the form of, Fig. 7 .I

Fig.7. is a.

cat'ionof Fig. 4:; and

While the invention may be applied to Y other types 'o ftool, it will bedescribed in an embodiment intended for resurfacing the conical valveseats of internal combustion- 7 engines. When such valve" seats havebecome be scraped clean before they can be surfaced, to the degree ofaccuracy and finish required;

Due to the great hardnessof the carbon-coat ing, this has "previously;been a matter of incrusted with carbon andpitted they must greatdifliculty. as the tools used'would become dull rapidly and requirefrequent rebody of the cutter of an inexpensive material 1 such as castiron, and insertv inthis bodyteeth 1 of high quality, preferablyhardened only a'd-' ,1 soft portions-of theblades cushion thecutgrinding. These tools have generally been made of. high quality steelsuitably formed with cutting surfaces. i

. According to. my invention, I formthe jacenttheir cutting edges. 1Therelatively ting action, and allowthe blades to drag along the, surfaceto be "cleanedwith' an action much' likeaseries of scrapers, Thecushiom'MassAcHI-usn'rrrs, A companion or:

ing also"greatly reduces the chi pi gand" breaking down o'f thecuttingsurfaces. The 7 concentration of the high" quality' material intothe bladesywhich require'little' shaping'g' reduces the cosflofthfemain'bulk of the tool 55 s'o'that for-a given price a much higherquality steel can be used for the cutting elements,

' --The fo'r riof the invention shown in Figs;

1,' 2 and 3 will firstbe'consideredf The tool thereshown'cornprisesabody portion 10, preferably 'of'cast iron or 'ctherrelatively inexpensive "materiahihaving a conical surface 11 and areversely tapered surface- 12. A bore 13 egrtending axially througlrthebody -may be tapered or otherwise formed for 5 fitting upon a standardtool operating device. I Slots 14, here. shown as all directed to- Wardstheapex of the conical surface although they may be arranged in aslanting direction if desired, are formed in the surface 11.-

V V I v The-blades are formed from a strip of detail of a blade for themodifi- H j j 1 f 7g steel, hardened asindicated at 16 adjacent I Fig. 8isa. detail "of aI inodifiedHfOrm-of blade stock.

one edgelonly, the remainder of the width 15 of the strip beingrelatively soft and flexible.

Grooves 18 and 19 are provided on the surface 12 and on the other endofthe body portion respectively, into which the slots 14: extend. Afterthe blades have been inserted in the slots 14, their end portions aredistorted into the grooves 18 and 19 as by a prick punch or "by peening.This permanently secured the blades in place andthey may'novv be groundtrue, when the cutter is ready for "as use.

In Figs. 4 and 7, I have shown an'alterna-v 1 tive way of securing theblades in place which is particularly useful in cases where distortedinto grooves in the base as in the case just described. In this modifiedform, the'blades" are notched as at 22 at their ends, and when 7 theyare inserted into theslots 14 in the body 935 24 here made withoutthefend grooves), the body o'fthetool is distorted, by prick punch'rnarks, 'pe'ening for otherwise, into the notches 22.

a It may be desired in someinstances to Km the blade is hardenedthroughout its width to J and therefore cannot vbe give a rough toolingto the valve seat before I v Ismoothing it up in order to remove heavycarbon deposits. In this case, teeth 27' may be formed in the hardenedside 28 of the 1 blade strip. In assembling these toothed v ,1 bladesinto the tool body, teeth of adjacent 1 bladesareperfe rablyoffset inorder to avoid r a 7 grooving the valve surface. A convenient l a Way ofdoing this is to provide a fixture j j V. which will engage the teeth ofthe blades and hold'them positively in a spiral or other de-;: V siredrelation until they are secured perma 7 nently.. v. V

WhatI'o1aim is: 'i r 3.; J p 15 3A valve seat cuttingftoolhaving a bodyportion in; the form; of a truncated icone, slottedin the coniealwallsthereof, a plural ity of blades tightly fitting into; said slots and]extending outwardly therefrom, each 20 bladehaving a hardened cuttingportion adjacent its outer edge with that part enclosed in the slot:anda part of the 'outwardlyprojeoting portion relatively resilient, andgrooves in thevbodyfportionjadjacent the 25 ends of the blades, thebladeends having re1a-; tively soft portions offset into said grooves vto hold the blades against displacement. 4 testimony whereof I haveaffixed-my; i signaturefi 1 o ,BYRONIIFIQJS'IOWELL.

